Mayweather Sr., whose famous son fights Alvarez in a megafight blockbuster Saturday at MGM Grand here, said his past relationships with members of Alvarez's camp have paid off in valuable inside information -- most notably, he said, that the Mexican star is having difficulty with the weight limit.

Weight has been an issue around Mayweather-Alvarez since the fight was signed because it's a super welterweight unification, yet the contracts mandate a 152-pound limit, two pounds beneath the division limit.

Mayweather Sr. said Alvarez might not make it, despite a recent advance weigh-in which didn't disclose any problems.

So how would the opposing trainer know such a detail?

"I have people in his camp," Mayweather Sr. said. "I've been talking to them all the time. Quite a while."

And what do they tell him?

"What is what," Mayweather Sr., who trains his son, said coyly.

Specifically, the trainer said people close to Alvarez have disclosed that the World Boxing Council champion is having a devilish time making weight and that last Friday's advance weigh-in, where Alvarez was less than six pounds over the limit, was deceiving.

At that WBC-mandated weigh-in, which occurs one week before championship bouts and requires fighters to be no more than 5 percent heavier than the weight limit, Alvarez scaled 157.4 pounds, well within the requirement.

Alvarez was 159.2 at the seven-day check before his last fight, against Austin Trout, at the full division limit.

Getting down to 152 is a different story than 154, and Mayweather Sr. said people close to Alvarez have told him there isn't anything but water left to lose.

Mayweather Sr., who for six years trained Golden Boy Promotions founder Oscar De La Hoya, still has an array of friends in that group.

Golden Boy promotes Alvarez and has high hopes that its current flagship fighter can unseat Mayweather in the showdown of unbeatens.

Mayweather Sr. said that his old friends sometimes can't help disclosing valuable information when visiting Las Vegas, and that he often insists they do so just to gain access to his son.

"So they tell me their business, man," he said.

Conversely, with some 250 people crammed into Mayweather Boxing Club just to watch a non-sparring, taper-down workout on Monday, and large crowds for most of training camp, it's difficult to imagine that Alvarez couldn't also glean some inside information through those channels.

"I'm very much aware that when they come up here ratting at me, they're going back ratting, too," Mayweather Sr. said.

While many boxing traditionalists chastised the Mayweather camp for the 152-pound limit, Mayweather Sr. has said he would have pushed for an even harsher limit of 150.

Now, he said he believes that "152's gonna get him (Alvarez) in big trouble, too."

"That's a big-boned guy," he said. "He's thick, man. So when he comes down -- man, I'm just waiting to look to see how he looks when he comes down. Because I know when he (makes weight), he's going to be looking very sick in the face, believe me.

"He ain't going to be the same Alvarez. You better believe what I'm telling you right now. You understand? And when he gets his ass up in there, he's going to find out himself he's sick."

-- David Mayo has covered Floyd Mayweather throughout the boxer's career. Contact him at dmayo@mlive.com